Fender started to produce the Stratocaster or Strat in the spring of 1954. Fenders first month of production for the Strat was about April, though there are some prototypes with earlier dates.  

Earlier vintage 1954 Strats, within the first two months of production, are slightly different than later vintage 1954 Strats. Some of the most obvious noticeable traits of the very early (first 200) 1954 Strats are:

• Serial number on the plastic tremolo cover plate instead of the metal neck plate.

• The bakelit knobs are a slightly different shape, with smaller "skirts".

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• The Strat case is shaped like the guitar (known as a "poodle" case) instead of a center pocket rectangular tweed.

Early Strats are made from one piece Ash bodies which makes the weight of the guitar to be medium to light, which is fairly rare. Generally 1954 models tend to be heavy. Ash bodies were used on Fender Strats until mid-1956, when Fender switched to Alder (for all colors except Blond). The Ash wood grain is much prettier. The way Fender finished sunburst Ash bodies is slightly different than how they finished Alder sunburst bodies, so the overall look of the sunburst is slightly different too.

Fender didn't always put a body date in the pot of the Stratocaster. Sometimes it's in the middle pickup route on the front of the body during the 1950's. By the early 1960's, body dates were no longer the norm. By the mid 1960's, it is very rare to find any Fender with a body date.

Fender maintained neck dates until about 1970, but the signing of the neck by the craftsmen stopped about 1955 or 1956, so if you see initials or signatures you will be aware of the date the Stat was made.

There should be "nail holes"in the Strat body. Nails used to hold the body when being painted. A finish nail is driven into the body at four positions to act as "feet" to elevate the body during finish spraying, and to allow it to dry. Later the nails are removed and discarded. The four nail holes should always be evident and NOT filled with paint! If the nail holes are missing or have paint in them, the body was refinished. Fender used this nail technique until about late 1964.

Underneath the single layer pickguard. All white single layer Fender pickguards from 1954 to 1959 were made from a new material (at that time) called ABS or vinyl. These pickguards are not bakelite! (though the knobs and pickup covers are often called "bakelite", they are actually polystyrene). The small aluminum sheilding plate under the pots and switch increased in size and decreased in thickness in 1959.

On the back of the peghead there is a tooling hole underneath the tuners, between the "G" and the "D" tuner. This hole was used when the neck was made. Fender mantained this tooling hole until the late 1960'.

The back tremolo cover plate has string access holes that are round. Starting in early 1955, these holes changed to an oblong shape. This allowed the strings to be changed easier with this cover in place.

The Stratocaster tremolo as used from 1954 to early 1971. The bridge saddles are stamped "PAT. PEND." opposed to reissue Strat saddles which are stamped "FENDER FENDER" instead.

Information was taken from http://www.provide.net/~cfh/strat54.html